MPS160

MPS160 is a synthetic peptide vaccine derived from the melanoma antigen glycoprotein 100 (gp100), corresponding specifically to amino acids 175–189 (sequence: GRAMLGTHTMEVTV). It contains overlapping epitopes that bind both HLA class I (A2) and class II (DR53, DQw6) molecules, and is designed to elicit cytotoxic T lymphocyte responses in melanoma patients. Developed as a cancer immunotherapy, specifically for metastatic melanoma, MPS160 was evaluated in a randomized Phase II clinical trial for its safety and immunologic efficacy. The vaccine regimen involved repeated subcutaneous administration with incomplete Freund adjuvant (Montanide ISA-51), either alone or in combination with recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF). Preclinical studies showed promising immunogenicity and antitumor activity; however, in the clinical trial, MPS160 generated vaccine-specific, but nonfunctional, cytotoxic T cells and failed to induce objective tumor responses in patients. Its lack of functional efficacy was attributed to systemic immune dysfunction in advanced melanoma[1][2][4][7].